The S&P 500 was off 0.42% to 1,403 in midday trading Monday.
The Nasdaq was up 0.04% to 2,968, while the Dow Jones Industrial Average was down 0.51% to 12,943.
The yield on a 10-year treasury bond fell 2.13% to 1.66%.
The price of gold was off 0.07% to $1,750 per ounce.
Shares of Anaheim drug maker Questcor Pharmaceuticals Inc. rose about 3% to $27 for a market value of $1.6 billion.
American Vanguard Corp. was up about 2% to $34. The Newport Beach-based specialty chemicals maker had a recent market value of $946 million.
Irvine-based Impac Mortgage Holdings Inc. was up about 15% to $14 for a market value of $112 million.